In co-pending U.S. patent applications Ser. No. 354,586, filed June 22, 1989 and Ser. No. 387,265, filed July 31, 1989, are disclosed basic zeolites containing excess alkali metal or alkaline earth metal over that required to fully exchange the zeolites. These basic zeolites are useful for catalyzing basic reactions.
It has now been found that by replacing all or part of the alkali or alkaline earth metal with zinc, a "softer" basic zeolite can be made.These soft zeolites can be used to catalyze those organic reactions wherein the use of stronger bases would cause degradation of the reacting organic substrate or reaction products. The use of a soft base such as zinc in the preparation of basic zeolites can result in higher retentions of zeolite crystallinity than does the use of the stronger bases such as alkalis and alkaline earth metals.